1. Field of the Invention
The present invention relates to a haptic sense rendering apparatus that renders haptic information through movement of a haptic sense rendering unit and a method of driving such a haptic sense rendering apparatus.
2. Description of the Related Art
In recent years and continuing, haptic sense rendering apparatuses are being developed for use in operations control devices such as an input unit of a computer, an operations unit of an audio apparatus, and an operations unit of a car navigation system that is installed in a vehicle. Such haptic sense rendering apparatuses are designed to convey information to an operator by rendering a haptic sensation via a haptic sense rendering unit so that the operator may feel a force at his/her fingertips upon touching the haptic sense rendering unit with his/her fingertips.
A flat mobile haptic sense rendering apparatus may have four magnets arranged flat on a plane and drive coils arranged above and parallel to these four magnets, and a thrust may be generated by supplying electric currents through these drive coils, for example. That is, by arranging plural drive coils to face plural magnets that are arranged flat on a plane and controlling the electric current being supplied to these drive coils, a desired force may be generated by the drive coils to thereby cause relative movement of a haptic sense rendering unit. It is noted that Japanese Patent Laid-Open Patent Publications No. 2000-330688 and No. 2004-145748 disclose examples of flat mobile haptic sense rendering apparatuses that implement such a configuration.
In the case of using such a haptic sense rendering apparatus in an input device of a computer or an operations unit of a vehicle, it is desired that the apparatus be miniaturized and the thrust generated by the drive coils be increased.
However, in order to increase the thrust to be rendered by the haptic sense rendering apparatus as is described above, the magnetic fields of the magnets have to be increased or the electric currents supplied to the drive coils have to be increased. To increase the magnetic fields of the magnets, suitable materials may have to be selected or the volume of the magnets has to be increased. It is noted that selecting suitable materials for the magnets may lead to cost increase. Also, in the case of increasing the volume of the magnets, miniaturization of the apparatus may be hampered.
Thus, in order to increase the thrust generated by the drive coils, the electric current supplied to the drive coils has to be increased. However, increasing the electric current supplied to the drive coils may lead to an increase in heat generation. This may be a problem since heat dissipation performance is degraded when the apparatus is miniaturized and heat generation per unit volume may be increased as a result.
Accordingly, there is a demand for a haptic sense rendering apparatus that is small in size and is capable of rendering a strong thrust without causing an increase in heat generation.